Given a rectangle that is 60 cm long and 15 cm wide, find the length of another rectangle whose area is equal

| April 26, 2021 | education

Given a rectangle that is 60 cm long and 15 cm wide, find the length of another rectangle whose area is equal to the area of the given one and its width is 5 cm less than the first rectangle.

When solving the problem, we will use the formula for calculating the area of ​​a rectangle:

S = a x b, where S is the area of ​​the rectangle, a is the length of the rectangle, in is the width of the rectangle.

1) Find the area of ​​the first rectangle:

S1 = 60 cm x 15 cm = 900 cm2.

2) The area of ​​the second rectangle is equal to the area of ​​the first rectangle by the condition:

S2 = 900 cm2.

3) Find the width of the second rectangle:

15 cm – 5 cm = 10 cm.

4) We substitute the data known about the second rectangle into the formula for calculating the area of ​​a rectangle (we denote the desired length as x) and we get the equation:

10x = 900.

x = 900: 10.

x = 90 (cm).

Answer: the length of the second rectangle is 90 cm.



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